A lot of you tried to create a DAG (database Availability Group) with Microsoft Exchange 2013. Me too…So a lot of you get many errors when you tried to add DAG member. Most of issues are found with the couple Active Directory under Windows Server 2012 + Exchange Server 2013. Most of issues and error list below are not present if you are using an Active Directory under Windows Server 2008 R2.
So you’ve installed two Exchange 2013 with the Mailbox role and you decide to create the DAG with those two server. So you create a DAG…so good so far, no errors 🙂
Now you decide to add the first member to your DAG. Hello problems 😉
First Issue: ACCESS DENIED
A server-side database availability group administrative operation failed. Error The operation failed. CreateCluster errors may result from incorrectly configured static addresses. Error: An error occurred while attempting a cluster operation. Error: Cluster API ‘”CreateCluster() failed with 0×5. Error: Access is denied”‘ failed.. [Server: MBX1.fabrikam.int]
Cause: the ECP wizard tried to add the first mailbox server to the DAG. During this process the wizard create a computer object in Active Directory (the CNO). This object don’t have the good rights. Exchange Trusted Subsystem had special permissions assigned and not “Full Control” on CNO.
Resolution: assign “Full Control” to Exchange Trusted Subsystem on the CNO.
Second Issue: DNS Host Name
An Active Manager operation failed with a transient error. Please retry the operation. Error: The fully qualified domain name for node '<DAG Group Name>' could not be found.
Cause: if you go in the property of the CNO, in the tab ‘general’, you will see the field “DNS name” empty. The ECP cannot find this information, that’s why you have this message.
Resolution: go in the property of the CNO, in the tab ‘attribute’ tab and search for the “dNSHostName” attribute. Enter the FQDN of the CNO and apply.
Third Issue: CNO not disable
A computer account named 'mydag2' already exists and is enabled. The account must be disabled in order to be used by the database availability group.
Cause: the CNO is enable. To operate the ECP need to have the CNO disable. The ECP will enable the CNO himself.
Resolution: GO in Active Directory and disable the CNO.
ok now you can add your mailbox server to your DAG 🙂 Well just one last question: why the ECP failed to create correctly the CNO? I don’t have this answer but if you read the technet article “Managing DAG” you will find a section named “Pre-staged the Cluster Network Object for DAG”.
This section explain to you that you can pre create the CNO manually and disable it. If you follow this technet you should not have the issue 1 and 3 describe in the post. However you will still have the issue 2 or you will have to change the attribute “dNSHostName” during the creation of the CNO (the best way to do FMO).